Mar 042011

By Tammy Gray-Searles —

“Cloud seeding technology is one of several technologies available to maintain snowpack. It’s being practiced in every Colorado River Basin state, except Arizona,” said Northern Arizona University Professor Dr. Rand Decker.

Decker, who is also a faculty affiliate for the Arizona Water Institute, spoke to the Navajo County Board of Supervisors on Feb. 22 about the potential for cloud seeding in Northern Arizona. Following the meeting, he explained to The Tribune-News that there are no existing plans for such a project, but a dialogue about the possibilities has been started.

Decker made a presentation to the Little Colorado River Conservation District, and was then asked to provide the Board of Supervisors with the same information.

“People are interested in getting information about it (cloud seeding),” he said. “It’s not accurate to say it’s being considered. It is accurate to say it’s being talked about.”

Cloud seeding involves spraying silver iodide into the air, which encourages moisture in clouds to turn into snow. According to Decker’s presentation, cloud seeding could augment snowpack by seven to 11 percent. He noted that the area is in a 17-year winter drought that might be eased with proper use of cloud seeding technology.

In addition to increasing snowpack and streamflow, if successful, a cloud seeding project would increase the water supply for portions of southern Arizona, as well. He noted that the Central Arizona Project supports snowpack augmentation.

Decker said that he is not advocating for cloud seeding, but would like to see serious discussion take place about whether it is a viable option for Northern Arizona.

“It is a mechanism for dialogue for what technology there is, and whether Arizona might take it up or not,” he remarked.

Critics of cloud seeding cite potential long-term environmental hazards and argue that there is no proof the process actually results in increased snowfall. They also cite high monetary costs as a downside to the technology.

Proponents claim that using silver iodide to help form ice crystals is safe, and that areas where cloud seeding has been in place for years do not show increased concentrations of the substance. They also note that it does appear to increase snowpack and it is less expensive than many other alternatives.

According to Decker, “augmented snow-water cost estimates are $6 to $18 per acre-foot.” He pointed out that in Utah, cloud seeding project areas had increased precipitation of three to 21 percent during the project.

He also noted that planning studies for Arizona are estimated to cost $60,000 to $100,000, and an implementation trial would cost about $200,000.

A proposal is being developed for U.S. Forest Service support of a cloud seeding trial.

Decker noted, “What’s important for the public to know is that Arizona stands out in its absence of having any sort of program. All the other Colorado River Basin states have snowpack augmentation programs.”